Terrain modeling using the half-plane geometry with applications to ILS glide slope antennas

A technique for modeling ground terrain is presented. The analysis is based on resolution of the ground in question into semi-infinite planes or strips. Using the half-plane solutions for diffracted radiation developed by Senior, Woods, and Bromwich it is shown that with slight modification, the effects of arbitrarily oriented dipole and ground planes can be considered. Application of the modeling is presented for instrument landing system (ILS) glide slope arrays. The results show close correlation between the theoretical and experimental DDM and signal patterns. For transverse half-planes the capture effect and sideband reference systems out-perform the null reference, whereas for lateral edges close to the antenna the reverse is shown to be true. This is in agreement with the relative ground currents characteristic of each antenna.